Heavy duty heaters for gases



Oct. 22, 1963 L. P. HYNES HEAVY DUTY HEATERS FOR GASES Filed June 27,1962 4 Sheets-Sheet 1 llll INVENTOR Lee flywai ATTORNEYS Oct. 22, 1963L. P. HYNES HEAVY DUTY HEATERS FOR GASES 4 Sheets-Sheet 2 Filed June 27,1962 llllllllllll l.

INVENTOR Lee K @1280 Oct. 22, 1963 Filed June 27, 1962 L. P. HYN ESHEAVY 'DUTY HEATERS FOR GASES 4 Sheets-Sheet 3 I VENTOR Lee @056 e g...1.. Q5,

ATTQRNEYS Oct. 22, 1963 1.. P. HYNES 3,103,174

HEAVY DUTY HEATERS FOR GASES Filed June 2'7, 1962 4 Sheets-Sheet 4INVENTOR Lee E #yner are likely to be gases.

United States Patent 3,108,174 HEAVY DUTY HEATERS FOR GASES Lee I.Hynes, Haddoniield, Ni, assignor to Hynes Electric Heating (10.,Kenilworth, N..l., a corporation of New Jersey Filed June 27, 1962, Ser.No. 205,647 Claims. (Cl. 219--38) The present invention relates toelectric heaters for fluids, especially gases, including air.

A purpose of the invention is to provide a more flexible arrangement influid heaters.

A further purpose is to utilize a casing to continuously support aheater.

A further purpose is to provide a heater frame formed of metal segments.

A further purpose is to eliminate supporting bearings for the heaterelement.

A further purpose is to provide a more simple arrangement wherein theentire heater assembly is prefabricated outside the heater pipe orcasing and then inserted into a pipe or casing.

A further purpose is to eliminate supports for the heater structure inthe form of cross pieces welded in the casing.

A further purpose is to eliminate the necessity for access to both endsof a casing to insert the heater in the casing, since the heater isself-supporting without,

end bearings.

A further purpose is to provide a prefabricated selfsupporting heaterassembly rigid enough to be safely shipped to a point of installationand which can be readily inserted into a casing which has already beeninstalled.

A further purpose is to utilize the frame to protect the ceramicinsulators from damage during shipment, installation and use.

A further purpose is to protect the resistor ribbons from mechanical andelectrical damage by supporting them freely between insulators.

A further purpose is to enable a heater to be inserted into a casingfrom one end only of the casing.

Further purposes appear in the specification and in the claims.

In the drawin s 1 have chosen to illustrate a few only of the numerousembodiments in which my invention may appear, selecting the forms shownfrom the standpoints of convenience in illustration, satisfactoryoperation and clear demonstration of the principles involved.

FIGURE 1 is a fragmentary perspective view of the heater of theinvention with the casing broken away.

FIGURE 2 is a fragmentary axial section of an electric heater inaccordance with the invention, omitting the extended portions of thecasing at the ends, taken on the line 2-2 of FIGURE 3.

FIGURE 3 is an end view partly in section, showing the heater of theinvention.

FIGURE 4 is a fragmentary section taken on the line 4-4 of FIGURE 3.

FIGURE 5 is an end view of a variation of the heater of the invention.

FIGURE 6 is an enlarged fragmentary exploded view of the heater of theinvention without the resistor ribbons.

Describing in illustration but not in limitation and referring to thedrawings:

The present invention is applicable to the heating of fluids, which maypermissibly be liquids, but in most cases When reference is made hereinto gas or gases, it is intended to include air and one of theadvantageous uses of the present invention is to heat air for testingguided missiles, jet engines and for use in Wind tunnels and the like.

The invention is particularly applicable for heating gases under highpressure and high temperatures. For example, the invention could be usedto heat gas under a pressure of 5,000 p.s.i. to a temperature of 1800 F.

The invention is also applicable for heating gases utilized for examplein the chemical industry. One example is heating of hydrogen andnitrogen which are being passed over a catalyst suitably at severalthousand p.s.i. and at elevated temperatures. which may be as high as1700 F. or more in order to make ammonia. Many of the installations inwhich the equipment of the invention will be applied are characterizedby high temperature alone or by high pressure alone or both hightemperature and high pressure.

The invention is applicable also to installations embodying intermediateand low pressure and also to those in which moderate pressure ortemperature is employed.

The invention is concerned with a heater which extends parallel to afluid flow in a pressure vessel or casing of generally cylindricalshape.

My patent for Fluid Electric Heater, 2,790,889, granted April 30, 1957,provides a very satisfactory heater of the above type. It is necessary,however, to suspend the heater elements and insulators from a centrallongitudinal rod-like element supported by bearings at both ends fromabutments welded or otherwise joined to the casing. The presentinvention eliminates the need for central bearing by utilizing alongitudinally extending segmented frame which rests against the casingwalls, thereby utilizing the casing itself to support the heater.Furthermore, the present invention utilizes a radial arrangement of thesegmented frame to provide strength and protection for the electricalelements.

In accordance with the invention, a frame is assembled from sheet metalwelded or otherwise connected together. The frame acts to supportradially spaced insulators which receives radially directed,longitudinally extending resistor ribbons. The insulators and resistorribbons are held in place between the frame members by retainingelements. The frame rests on and is supported within a pressure casing.

The fiuid to be heated passes through casing 20, such as a pipe orcylinder, of sufficient structural strength to withstand the fluidpressure. A heater 2i. rests within the casing. The heater 21 comprisesa frame 22 which extends longitudinally for the length of the heater.The frame 22 is composed of frame segments 23 which may be of anydesirable metal, for instance, stainless steel, Inconel, high chromesteel or of a nickel alloy of any type material capable of withstandingthe high fluid temperatures.

The frame segments 23 have radial flanges 24 which extend from a base25'. The base 2:"? extends in a plane normal to a plane bisecting theangle included by the radial flanges 24. The base 25 can be of any widthbut desirably the width of the base will be such as to give adequatesupport to the electrical elements as will be explained. The base 25 hasa plurality of spaced holes 26 spaced longitudinally of the segment 23.

The segments 23 extend longitudinally in circumferential relationshipwith the radial flanges 24 abutting. The number of segments used will bedetermined by the angle at which the radial flanges 24 are disposed toone another in an individual segment. For instance, in the form ofFIGURE 3 the segments have radial flanges which form an included angleof substantially so that three segments circumferentially disposed toone another would be necessary to form a complete frame 22. ()n theother hand, in the embodiment of FIGURE 5, the radial flanges in anindividual segment form an included angle of substantially 60 so thatsix segments would be ararcane ranged circumferentially to form theframe 22 for the heater.

The angle at which the radial flanges are disposed to one another in anindividual segment is determined primarily by the heater diameterwherein generally speaking, the larger the diameter the smaller theincluded angle formed by the flanges and the greater the number ofsegments necessary. For instance, in FIGURE 3 the diameter isconceivably six inches while in FIGURE the diameter could conceivably betwelve inches.

The frame segments 23 are joined as by welding along their abuttingradial flanges 24 as, for instance, at 27.

The bases 25 of the frame segments will form in cross section a regularstraight sided figure which will vary depending on the number ofsegments used. These will include the triangle shown in FIGURE 3 and thehexagon shown in FIGURE 5.

At the base of the segments and guided by the radial flanges, I place atspaced longitudinal positions an inner insulator of suitable ceramicmaterial which conforms at its radial inward side to the contour of theframe segment 23.

The insulator 30 has a base 31 and radial faces 32 and 33. The radialoutward surface 34 of the insulator 39 is circumferential. Thecircumference 34 has a plurality of circumferentially spaced grooves 35which extend in a direction longitudinal of the heater. The ceramicinsulators 30 have a length 36 which may vary in order to give adequatesupport in the heater but which, for instance, can be of the order oftwo inches. On the base 31 there extends a boss 37 which conforms incross section to the opening 26 in the segment base 25. The insulator3i) rests against the base 25 with the boss 37 extending through theopenings 26. The purpose of this is to position the insulators 30longitudinally in the frame segment 23. It should be understood that anysuitable means may be used in place of the boss and holes to positionthe insulators. For instance, ears could be lanced from the framesegments 23 to engage the insulators.

Resistor ribbons 40 extend longitudinally along the heater and lie inradial planes. The radially inward edge of the ribbon 4t) rests and issupported by the grooves 35 in the insulator 39. The radially outer edgeof the ribbon rests at 42 in grooves 43 of outer insulator 44. The outerinsulator has an inner circumferential face 45, an outer circumferentialface 46, transverse faces 47 and 48, and radial faces 50 and 51.

The inner circumference face 45 with longitudinally extendingcircumferentially spaced grooves 43 suitably positions and secures theresistor ribbons 40.

The outer circumferential face 46 has a circumferentially extendinggroove 52 which receives a clamp 53 of desirably arcuate shape havingoffset portions 54. The radial flanges 24 of the frame are of suflicientlength in a radial direction to receive the offset 54 when the clamp 53is exerting a retaining force on the insulator 44 and the offset 54 isjoined to the flange 24 at 55 as by welding or the like. The purpose ofclamp 53 is to retain the insulator 44 longitudinally and radially. Itshould be understood that although the clamp 53 is shown as a continuousare, any suitable form which accomplishes the purpose of locating theinsulator 44 may be used. However, by using a continuous arc clamp, wehave the added advantage of a structural tie which bridges the radiallyextending flanges 24.

As best seen in FIGURE 1, the insulators 30 and 44 and the clamp 53 arespaced longitudinally along the heater frame 22 to yield adequatesupport of the resistor strips 40. This longitudinal spacing is a matterof choice and may vary to achieve any desired stiffness.

Current is arranged to pass in series through selected groups ofresistor ribbons 4i) and for this purpose electrical jumpers 56 arewelded to adjoining arms of every alternate pair of resistor ribbons atone end of the heater and jumpers are welded to the adjoining arms ofevery intervening pair of resistor ribbons at the opposite end of theheater, thus providing for current flow in zig-Zag relationship(series). The groups are selected on the basis of the electrical phasearrangement desired. For instance, in the case of a single phase for theentire heater, the current would pass through all ribbons in series.This would also be true in the case of a heater utilizing directcurrent. For a three phase heater, the heater of FIGURE 3 for instancewould be arranged so that the six ribbons in each of the three framesegments would be connected in series for each phase. In FIGURE 5, forinstance, the ribbons in any two adjacent segments could be connected inseries to form one phase. The jumper 56 may be, for instance, heliarcwelded to the ribbons 49. The jumper is welded to the ribbons so thatthe metal of the jumper is edgewise to the flow of the fluid.

The electrical connections are conveniently made through leads 60 whichmay extend longitudinally of the heater and connect through terminalstrip 61 of the heater. The leads 60 are brought through the casing wallby suitable insulated pressure type seals.

. It should be understood that the basic structural support of theheater comes from the casing itself, since the frame 22 of the heaterrests against the casing.

However, the frame also has inherent strength by virtue of theararngement wherein the flanges of the frame extend radially.

In assembling the heater of the invention, the frame segments 23 areplaced in a longitudinally extending, circumferentially displacedrelationship so that the flanges 24 are spaced symmetrically within acircle and are welded or otherwise joined at 27. Inner insulators 30 areplaced on the base 25 of each of the frame segments 23 with the boss 37extending through a hole 26. Resistor ribbons are placed longitudinallyin the slots 35 of resistor 36 so that they extend radially in thecircle formed by the segments. Outer insulators 44 are then placed onthe resistor ribbons 40 so that the grooves 43 receive the resistorribbons.

Clamps 53 are then placed in the grooves 52 of the insulators 44 and theoffsets 54 are then joined as by welding to the flanges 24 at 55. Theelectrical jumpers 56 and tenminal strips 61 are then welded in place,and the terminals 60 installed.

In inserting the heater 21 in the casing 20, access is only necessary toone end of the casing. The heater is merely inserted in the end andpushed into the casing.

Suitable provision is made for anchoring the heater frame 22 at theterminal end, so that heat expansion and contraction can take placewithout creating stress on the electrical terminals. This would alsopermit mounting the heater casing vertically with terminals at thebottom end.

In view of my invention and disclosure, variations and modifications tomeet individual whim or particular need will doubtless become evident toothers skilled in the art, to obtain all or part of the benefits of myinvention without copying the structure shown, and I, therefore, claimall such insofar as they fall within the reasonable spirit and scope ofmy claims.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

l. A fluid heater including a generally cylindrical casing, a selfcontained resistor unit within said casing comprising a longitudinallyextending frame in abutting relation with the inner surface of thecasing and having at least three spaced radially outwardly extendingframe elements forming with the inner surface of the casing at leastthree longitudinally extending resistor receiving passageways, aplurality of longitudinally spaced and positioned inner insulatorssupported on the frame adjacent the radial inward portion of each of thepassageways and each having a plurality of longitudinally extendingoutwardly directed slots spaced apart along the outer periphery thereof,resistor ribbons extending longitudinally through the passageways inradial planes, the radial inner edges of said ribbon being positioned insaid slots in said inner insulators, a plurality of longitudinallyspaced and positioned outer insulators each supported between anadjacent spaced pair of said radially directed elements of said frameand occupying the radially outward portion of said passageways and eachhaving a plurality of longitudinally extending inwardly directed slotsspaced apart along the inner periphery thereof, said slots receiving andsupporting the radial outer edges of said resistor ribbons, and clampsextending from each radially directed frame element to the next andsecured at opposite ends to the outer portions of said radially directedelements, said clamps retaining said outer insulators, ribbons, andinner insulators in assembled relation.

2. A fluid heater of the character indicated in claim 1, whereininterlock means are provided between the inner insulators and the frameto limit relative movement thenebetween. 1

3. A fluid heater of the character indicated in claim 2, wherein saidinterlock comprises at least one projection on each of said innerinsulators and corresponding projection receiving openings in saidframe.

4. A fluid heater of the character indicated in claim 1, wherein theouter periphery of each of said outer insulators is provided with agroove and said clamps are seated in said grooves and restrain saidouter insulators against longitudinal movement.

5. A fluid heater of the character indicated in claim 3, wherein theouter periphery of each of said outer insulators is provided with agroove and said clamps are seated in said grooves and restrain saidouter insulators against longitudinal movement.

References Cited in the file of this patent UNITED STATES PATENTS2,058,769 Brown Oct. 27, 1936 2,536,747 Hynes Jan. 2, 1951 2,790,889Hynes Apr. 30, 1957

1. A FLUID HEATER INCLUDING A GENERALLY CYLINDRICAL CASING, A SELF CONTAINED RESISTOR UNIT WITHIN SAID CASING COMPRISING A LONGITUDINALLY EXTENDING FRAME IN ABUTTING RELATION WITH THE INNER SURFACE OF THE CASING AND HAVING AT LEAST THREE SPACED RADIALLY OUTWARDLY EXTENDING FRAME ELEMENTS FORMING WITH THE INNER SURFACE OF THE CASING AT LEAST THREE LONGITUDINALLY RESISTOR RECEIVING PASSAGEWAYS, A PLURALITY OF LONGITUDINALLY SPACED AND POSITIONED INNER INSULATORS SUPPORTED ON THE FRAME ADJACENT THE RADIAL INWARD PORTION OF EACH OF THE PASSAGEWAYS AND EACH HAVING A PLURALITY OF LONGITUDINALLY EXTENDING OUTWARDLY DIRECTED SLOTS SPACED APART ALONG THE OUTER PERIPHERY THEREOF, RESISTOR EXTENDING LONGITUDINALLY THROUGH THE PASSAGEWAYS IN RADIAL PLANES, THE RADIAL INNER EDGES OF SAID RIBBON BEING POSITIONED IN SAID SLOTS IN SAID INNER INSULATORS, A PLURALITY OF LONGITUDINALLY SPACED AND POSITIONED OUTER INSULATORS EACH SUPPORTED BETWEEN AN ADJACENT SPACED PAIR OF SAID RADIALLY DIRECTED ELEMENTS OF SAID FRAME AND OCCUPYING THE RADIALLY OUTWARD PORTION OF SAID PASSAGEWAYS AND EACH HAVING A PLURALITY OF LONGITUDINALLY EXTENDING INWARDLY DIRECTED SLOTS SPACED APART ALONG THE INNER PERIPHERY THEREOF, SAID SLOTS RECEIVING AND SUPPORTING THE RADIAL OUTER EDGES OF SAID RESISTOR RIBBONS, AND CLAMPING EXTENDING FROM EACH RADIALLY DIRECTED FRAME ELEMENT TO THE NEXT AND SECURED AT OPPOSITE ENDS TO THE OUTER PORTIONS OF SAID RADIALLY DIRECTED ELEMENTS, SAID CLAMPS RETAINING SAID OUTER INSULATORS, RIBBONS AND INNER INSULATORS IN ASSEMBLED RELATION. 